ST. LOUIS
— JUST before the Gulf war began in 1990, Margaret Gilleo wanted to send an anti-war message to her neighbors in the wealthy St. Louis suburb of Ladue. When the city told her she couldn't display such a sign on her lawn, her message ended up being heard across the United States.

The court case of City of Ladue v. Gilleo has mushroomed into a nationwide debate about how far government can go in regulating signs on private property. Last week, the Supreme Court heard Ms. Gilleo's case, and a decision is expected this spring.

``Never in my wildest imagination did I dream this would go to the Supreme Court,'' Gilleo says.

``This is a case that involves political speech on private property,'' says Alan Howard, a St. Louis University law professor, ``and the United States Supreme Court has had very few of these kinds of cases.''

At issue is the balance between free-speech rights and the ability of governments to regulate environmental aesthetics and help maintain property values.

Protecting landscapes

``The city should have the right to prevent the visual blight and sign proliferation that plagues so many parts of our country,'' says Ladue's attorney, Jordan Cherrick. ``All we're trying to do is protect this beautiful landscape in Ladue, which we think of as a quality-of-life issue.''

The controversy began with a 2-by-3-foot sign that Gilleo bought for $4 from an activist group and pounded into her front lawn. It said: ``Say `No' to War in the Persian Gulf. Call Congress Now.'' Someone took the sign overnight, so Gilleo put up another one. When that sign was torn down, Gilleo called the police to file a complaint. ``They said: `You're not allowed to have signs in Ladue.' And I said, `What do you mean? This is America. We have a First Amendment that guarantees free speech.' ''

Gilleo was unaware of the local ordinance banning political signs. Just a few month earlier, when she had put up a yard sign in support of an environmental initiative, ``Nobody said a word,'' she recalls.

Ladue's attorney argues that the ban is necessary to keep signs from proliferating and marring the natural beauty of the winding, tree-lined lanes in this residential area where the average house is worth more than $300,000. Although ``for sale'' signs, road signs, and some commercial signs are allowed in this city of nearly 9,000 people, political signs are banned.

``The Supreme Court has required that real estate signs be allowed,'' Mr. Cherrick says. ``So what Ladue is trying to do is follow the Supreme Court's First Amendment jurisprudence and, at the same time, deal with the significant aesthetic problems.''

But with the help of the American Civil Liberties Union, Gilleo sued the city. A US district court judge ruled in 1991 that Ladue's ordinance was unconstitutional because it allowed some commercial signs but not political signs.

But Ladue then passed a new ordinance stressing its commitment to free speech but again banning political signs in the interest of maintaining ``privacy, aesthetics, safety, and property values.''

After the Gulf war began, Gilleo put a candle in her second-floor window and put up a small sign saying: ``For Peace in the Gulf.'' The city said that sign was also illegal, and the issue went back to court. Both the district court and the 8th US Circuit Court of Appeals ruled that the law violated Gilleo's free-speech rights.

The decision was based on a 1981 Supreme Court case known as Metromedia Inc. v. City of San Diego. San Diego's law banned billboards but made exceptions for traffic signs and some commercial signs, such as ``for sale'' signs. A fractured Supreme Court threw out the San Diego law, arguing that it favored commercial speech over noncommercial speech.

William Rehnquist, who is now chief justice of the court, characterized the decision in a dissenting opinion as ``a virtual tower of Babel from which no definitive principles can be clearly drawn.''

This case and others put governments in a Catch-22 situation, says Jules Girard, a professor of constitutional law at Washington University in St. Louis.

``How can you regulate signs without making some exceptions?'' he asks. Ladue's appeal to the Supreme Court may be an opportunity to resolve the confusion, he says.

``The question here is whether cities are going to have some discretion to deal with problems as they face them, or whether they will be put into a constitutional straitjacket,'' Cherrick says.

Rectangular flags are okay

During last week's oral arguments before the Supreme Court, the justices questioned the distinctions in Ladue's ordinance.

When Cherrick conceded that Gilleo could have flown her message from a rectangular flag but not from a pennant, Justice Antonin Scalia appeared amused. ``I don't understand any sense behind that,'' Justice Scalia said. ``Tell me why triangles are worse than rectangles.''

Despite the laughter, there is a serious issue here, Dr. Girard says. ``You can poke fun at the city of Ladue, but the fact remains that regulating signs is a very important community function. It seems unlikely to me that the court is going to do anything that will undercut that notion.''

On the other hand, Dr. Howard says: ``I don't see how Ladue is going to win. It would be an incredible victory for state regulatory and zoning authority and a real defeat for private-property rights and free-speech rights on private property. I just don't think that's going to happen.''